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Freenet: A Distributed Anonymous Information Storage and Retrieval System
- INTERNATIONAL WORKSHOP ON DESIGNING PRIVACY ENHANCING TECHNOLOGIES: DESIGN ISSUES IN ANONYMITY AND UNOBSERVABILITY
, 2001
"... We describe Freenet, an adaptive peer-to-peer network application that permits the publication, replication, and retrieval of data while protecting the anonymity of both authors and readers. Freenet operates as a network of identical nodes that collectively pool their storage space to store data ..."
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Cited by 1064 (12 self)
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We describe Freenet, an adaptive peer-to-peer network application that permits the publication, replication, and retrieval of data while protecting the anonymity of both authors and readers. Freenet operates as a network of identical nodes that collectively pool their storage space to store data files and cooperate to route requests to the most likely physical location of data. No broadcast search or centralized location index is employed. Files are referred to in a location-independent manner, and are dynamically replicated in locations near requestors and deleted from locations where there is no interest. It is infeasible to discover the true origin or destination of a file passing through the network, and difficult for a node operator to determine or be held responsible for the actual physical contents of her own node.
Replication Is Not Needed: Single Database, Computationally-Private Information Retrieval (Extended Abstract)
- IN PROC. OF THE 38TH ANNU. IEEE SYMP. ON FOUNDATIONS OF COMPUTER SCIENCE
, 1997
"... We establish the following, quite unexpected, result: replication of data for the computational Private Information Retrieval problem is not necessary. More specifically, based on the quadratic residuosity assumption, we present a single database, computationally-private information-retrieval scheme ..."
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Cited by 271 (17 self)
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We establish the following, quite unexpected, result: replication of data for the computational Private Information Retrieval problem is not necessary. More specifically, based on the quadratic residuosity assumption, we present a single database, computationally-private information-retrieval scheme with O(n ffl ) communication complexity for any ffl ? 0.
Computationally private information retrieval with polylogarithmic communication
- Advances in Cryptology—EUROCRYPT ’99
, 1999
"... We present a single-database computationally private information retrieval scheme with polylogarithmic communication complexity. Our construction is based on a new, but reasonable intractability assumption, which we call the Φ-Hiding Assumption (ΦHA): essentially the difficulty of deciding whether a ..."
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Cited by 256 (2 self)
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We present a single-database computationally private information retrieval scheme with polylogarithmic communication complexity. Our construction is based on a new, but reasonable intractability assumption, which we call the Φ-Hiding Assumption (ΦHA): essentially the difficulty of deciding whether a small prime> 2 divides ϕ(m), where m is a composite integer of unknown factorization. Our result also implies the existence of two-round CS proof systems under a concrete complexity assumption. Keywords: Integer factorization, Euler’s function, Φ-hiding assumption, private information retrieval, computationally sound proofs.
Evaluating 2-dnf formulas on ciphertexts
- In proceedings of TCC ’05, LNCS series
, 2005
"... Abstract. Let ψ be a 2-DNF formula on boolean variables x1,..., xn ∈ {0, 1}. We present a homomorphic public key encryption scheme that allows the public evaluation of ψ given an encryption of the variables x1,..., xn. In other words, given the encryption of the bits x1,..., xn, anyone can create th ..."
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Cited by 231 (7 self)
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Abstract. Let ψ be a 2-DNF formula on boolean variables x1,..., xn ∈ {0, 1}. We present a homomorphic public key encryption scheme that allows the public evaluation of ψ given an encryption of the variables x1,..., xn. In other words, given the encryption of the bits x1,..., xn, anyone can create the encryption of ψ(x1,..., xn). More generally, we can evaluate quadratic multi-variate polynomials on ciphertexts provided the resulting value falls within a small set. We present a number of applications of the system: 1. In a database of size n, the total communication in the basic step of the Kushilevitz-Ostrovsky PIR protocol is reduced from √ n to 3 √ n. 2. An efficient election system based on homomorphic encryption where voters do not need to include non-interactive zero knowledge proofs that their ballots are valid. The election system is proved secure without random oracles but still efficient. 3. A protocol for universally verifiable computation. 1
Fairplay — a secure two-party computation system
- In USENIX Security Symposium
, 2004
"... Advances in modern cryptography coupled with rapid growth in processing and communication speeds make secure twoparty computation a realistic paradigm. Yet, thus far, interest in this paradigm has remained mostly theoretical. This paper introduces Fairplay [28], a full-fledged system that implements ..."
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Cited by 229 (6 self)
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Advances in modern cryptography coupled with rapid growth in processing and communication speeds make secure twoparty computation a realistic paradigm. Yet, thus far, interest in this paradigm has remained mostly theoretical. This paper introduces Fairplay [28], a full-fledged system that implements generic secure function evaluation (SFE). Fairplay comprises a high level procedural definition language called SFDL tailored to the SFE paradigm; a compiler of SFDL into a one-pass Boolean circuit presented in a language called SHDL; and Bob/Alice programs that evaluate the SHDL circuit in the manner suggested by Yao in [39]. This system enables us to present the first evaluation of an overall SFE in real settings, as well as examining its components and identifying potential bottlenecks. It provides a test-bed of ideas and enhancements concerning SFE, whether by replacing parts of it, or by integrating with it. We exemplify its utility by examining several alternative implementations of oblivious transfer within the system, and reporting on their effect on overall performance. 1
Traffic Analysis: Protocols, Attacks, Design Issues and Open Problems
- PROCEEDINGS OF INTERNATIONAL WORKSHOP ON DESIGN ISSUES IN ANONYMITY AND UNOBSERVABILITY
, 2001
"... We present the traffic analysis problem and expose the most important protocols, attacks and design issues. Afterwards, we propose directions for further research. As we are mostly interested in efficient and practical Internet based protocols, most of the emphasis is placed on mix based constructio ..."
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Cited by 162 (0 self)
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We present the traffic analysis problem and expose the most important protocols, attacks and design issues. Afterwards, we propose directions for further research. As we are mostly interested in efficient and practical Internet based protocols, most of the emphasis is placed on mix based constructions. The presentation is informal in that no complex definitions and proofs are presented, the aim being more to give a thorough introduction than to present deep new insights.
Authentication and Integrity in Outsourced Databases
, 2004
"... In the Outsourced Database (ODB) model, organizations outsource their data management needs to an external service provider. The service provider hosts clients' databases and offers seamless mechanisms to create, store, update and access (query) their databases. This model introduces several re ..."
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Cited by 143 (8 self)
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In the Outsourced Database (ODB) model, organizations outsource their data management needs to an external service provider. The service provider hosts clients' databases and offers seamless mechanisms to create, store, update and access (query) their databases. This model introduces several research issues related to data security. One of the core security requirements is providing efficient mechanisms to ensure data integrity and authenticity while incurring minimal computation and bandwidth overhead. In this work, we investigate the problem of ensuring data integrity and suggest secure and practical schemes that help facilitate authentication of query replies. We explore the applicability of popular digital signature schemes (RSA and DSA) as well as a recently proposed scheme due to Boneh et al. [1] and present their performance measurements.
Exponential lower bound for 2-query locally decodable codes via a quantum argument
- JOURNAL OF COMPUTER AND SYSTEM SCIENCES
, 2003
"... A locally decodable code encodes n-bit strings x in m-bit codewords C(x) in such a way that one can recover any bit xi from a corrupted codeword by querying only a few bits of that word. We use a quantum argument to prove that LDCs with 2 classical queries require exponential length: m = 2 \Omega ( ..."
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Cited by 134 (15 self)
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A locally decodable code encodes n-bit strings x in m-bit codewords C(x) in such a way that one can recover any bit xi from a corrupted codeword by querying only a few bits of that word. We use a quantum argument to prove that LDCs with 2 classical queries require exponential length: m = 2 \Omega (n). Previously this was known only for linear codes (Goldreich et al. 02). The
Private queries in location based services: anonymizers are not necessary
- In SIGMOD
, 2008
"... Mobile devices equipped with positioning capabilities (e.g., GPS) can ask location-dependent queries to Location Based Services (LBS). To protect privacy, the user location must not be disclosed. Existing solutions utilize a trusted anonymizer between the users and the LBS. This approach has several ..."
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Cited by 133 (16 self)
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Mobile devices equipped with positioning capabilities (e.g., GPS) can ask location-dependent queries to Location Based Services (LBS). To protect privacy, the user location must not be disclosed. Existing solutions utilize a trusted anonymizer between the users and the LBS. This approach has several drawbacks: (i) All users must trust the third party anonymizer, which is a single point of attack. (ii) A large number of cooperating, trustworthy users is needed. (iii) Privacy is guaranteed only for a single snapshot of user locations; users are not protected against correlation attacks (e.g., history of user movement). We propose a novel framework to support private locationdependent queries, based on the theoretical work on Private Information Retrieval (PIR). Our framework does not require a trusted third party, since privacy is achieved via cryptographic techniques. Compared to existing work, our approach achieves stronger privacy for snapshots of user locations; moreover, it is the first to provide provable privacy guarantees against correlation attacks. We use our framework to implement approximate and exact algorithms for nearest-neighbor search. We optimize query execution by employing data mining techniques, which identify redundant computations. Contrary to common belief, the experimental results suggest that PIR approaches incur reasonable overhead and are applicable in practice.
Protecting Data Privacy in Private Information Retrieval Schemes
- JCSS
"... Private Information Retrieval (PIR) schemes allow a user to retrieve the i-th bit of an n-bit data string x, replicated in k 2 databases (in the information-theoretic setting) or in k 1 databases (in the computational setting), while keeping the value of i private. The main cost measure for suc ..."
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Cited by 133 (21 self)
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Private Information Retrieval (PIR) schemes allow a user to retrieve the i-th bit of an n-bit data string x, replicated in k 2 databases (in the information-theoretic setting) or in k 1 databases (in the computational setting), while keeping the value of i private. The main cost measure for such a scheme is its communication complexity.
